This invention relates to electronics packaging, and more particularly to packages with metal cavities for crystal oscillators.
Precise clocks for electronic systems are often generated by a crystal oscillator that is coupled to a crystal blank. The crystal oscillator applies a voltage difference across the crystal blank, causing the crystal blank to vibrate at a desired frequency. The crystal oscillator can then amplify and buffer this oscillating signal from the crystal blank to output a clock.
Crystal blanks can be packaged in various packages, such as dual-inline-pin (DIP) packages made of materials such as plastic, ceramic, or metal. However, DIP packages have pins that are inserted into holes in a printed-circuit board (PCB), thus requiring board space on both sides of the PCB.
Surface-mount packages have pins or leads that are bent to be parallel to the PCB surface, or may have solder balls or flat pads for soldering to one surface of the PCB. The surface-mount package does not require holes in the PCB, so only one side of the PCB is occupied by the surface-mount package, saving board space. Also, surface mount packages tend to be smaller than DIP packages.
Crystal blanks have been packaged in ceramic surface-mount packages. It is desirable to mount crystal blanks in metal packages for some applications. A lower cost packaging process may result, and development times may be reduced. A metal, surface-mount package for a crystal blank is desirable.